Neuromyotonia (NMT), so called Isaac's syndrome, is a rare disorder in which hyperexcitability of peripheral motor nerves leads to intermittent muscle contractions. It is characterized by muscle twitching at rest (visible myokymia), cramps, hyperhidrosis, paraesthesiae, mild muscle weakness. and impaired muscle relaxation, or pseudomyotonia. Electromyographic recording is a key diagnostic tool in detecting myokymia and neuromyotonia. Pathophysiology of neuromyotonia is claimed to be related immune disorder, autoimmune anti-voltage-gated potassium-channel antibodies and genetic mutation in potassium channel. KCNA1 (Kv1.1) mutation was mostly reported in a autosomal dominant trait. In the present study, we report a family affected with myokymia，worsening with elevated body temperature, febrile illness or spicy food. How the change in temperature influence clinical features of channelopathies is an interesting topic. Variant clinical severity of family members are recorded. The index patient has possible autoimmune mechanism involvement because of his clinical feature of myasthenia gravis with thymoma and hyperthyroidism. Further analyzing the genetic mutation in potassium channelopathy may provide researchers some pathophysiological insight into the Isaac's syndrome.

Further study details as provided by China Medical University Hospital:

Biospecimen Retention: Samples With DNA

Genomic DNA was extracted from each patient's peripheral blood leukocytes using Genomaker DNA extraction kit (Blossom, Taipei, Taiwan). The complete KCNA1 coding region, including the intron/exon boundaries, was amplified according to the procedure reported by Imbrici et al

Estimated Enrollment:

18

Study Start Date:

April 2010

Estimated Primary Completion Date:

March 2011 (Final data collection date for primary outcome measure)

Eligibility

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

Yes

Sampling Method:

Non-Probability Sample

Study Population

We interview and examine the family members directly at our hospital and home visit or indirectly by telephone visit.

Criteria

Inclusion Criteria:

The disease was initially diagnosed of Isaacs syndrome by two neurologist(Dr Tsai and Dr Yang). We will recruit family members of diseased patient and normal subjects for clinical, electromyographic and genetic studies.

Exclusion Criteria:

none

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01250704